The invention relates to a method for preventing a premature breakdown of an upward flow of water caused by the accumulation of portions of water slowed down by friction at boundary faces of an appliance for practicing aquatic sports, the water being passed upwards over a sloping bottom surface, and further relates to an aquatic sports appliance comprising a water reservoir having a sloping bottom surface in which water is passed from a feed nozzle along the lower rim of said bottom surface upwardly to an overflow along the upper rim of said bottom surface.